Meeting Abstract

P2.116  Monday, Jan. 5  Feeding preference of Strongylocentrotus franciscanus for aged versus fresh kelp STEPHENS, Tiffany/A*; BRITTON-SIMMONS, Kevin; University of Washington and Friday Harbor Laboratories; Friday Harbor Laboratories tiffany3@u.washington.edu

Detrital macroalgae, particularly kelp, is an important food resource for sea urchins and other animals in many regions worldwide. However, most of what is known about consumer preferences for kelp comes from feeding trials conducted using fresh tissue. Detrital kelp undergoes important biochemical changes as it ages that potentially change its palatability and nutritional content relative to fresh tissue. We investigated the feeding preference of the red sea urchin Strongylocentrotus franciscanus for fresh versus aged (7 and 14 days) blade tissue from the kelps Nereocystis luetkeana, Agarum fimbriatum, and Saccharina subsimplex. Urchins were offered fresh versus aged pieces of blade tissue from each kelp species and a choice was recorded when urchins began feeding on one of the two pieces offered to them. We found that for Nereocystis luetkeana and Saccharina subsimplex urchins preferred aged over fresh tissue and the strength of this preference increased with tissue age. In contrast, fresh Agarum fimbriatum was always preferred over aged tissue. These results indicate that aging can influence food preference and that the effect of aging varies among kelp species. In systems where consumers have access to both fresh and detrital kelp tissue it may be important to evaluate how aging of detrital material influences consumer preferences in order to understand patterns of resource use in the field.